It is well known in the art that when fermenting a microorganism in order to obtain a desirable enzyme, one or more undesirable enzymes are often also expressed by said microorganism. If these undesirable enzymes are not effectively inactivated they may cause huge stability problems during recovery of the desirable enzyme and/or during storage of the desirable enzyme. Even if these other enzymes do not cause stability problems they may indeed be unwanted as industry for many purposes requires a "pure" enzyme without side-activities.
In order to solve the above mentioned problem many suggestions have been put forward: Hoerle et al. disclose in U.S. Pat. No. 4,086,139 use of hypochlorite and chlorite ions to inactivate amylase in an amylase-protease mixture; Bock et al. describe in DD 216 955 that polygalacturonases may be removed from a pectinase mixture by adding urea, and DeStefanis et al disclose in EP 021 179 that Bacillus proteases may be inactivated in a protease-amylase mixture by adjusting the system to a pH between 5.0 and 7.0, buffering said mixture with a buffering agent, and heating said mixture to a temperature of from 40.degree. C. to 75.degree. C.
It is an object of the present invention to provide a method for inactivation of undesirable enzymes in a mixture of enzymes which method should have short process times, result in high yields, and at the same time be simple, inexpensive and compatible to industrial requirements.